One Hundred Years of the Rock Island Government Bridge

The historic Rock Island Government Bridge, built in 1896, united the East and West across the mighty Mississippi. It's an ideal example of American technology, creativity, and entrepreneurship. The bridge, located adjacent to Lock and Dam No. 15, consists of two riveted Pratt through trusses, five riveted Baltimore trusses, and a camelback center-pivoted swing truss. The paper discusses the unique problems encountered during construction of the bridge, as well as its upgradings and maintenance. Many projects have been undertaken in the 100 years since the completion of the bridge. In each case, the structure was designed as near state of the art, but with rapidly increasing loading of the equipment operated over the bridge, modifications have been necessary to strengthen the spans and floor systems, as well as nearly all the other components of the structure. Several changes also have been required due to the Mississippi River Navigation projects and the increased highway traffic. Repairs to combat the aging process were done annually as a routine matter. The bridge was the first major accomplishment of Chicago engineer Ralph Modjeski, who subsequently established a reputation as one of the country's leading bridge designers.